Brush block



E. P. SNYDER BRUSH BLOCK Jan. 18, 1955 2 Sheets-Sheet 1 Filed Dec. 21, 1953 INVENTOR. El lery P. Snyder BY I AGENT.

Jan. 18, 1955 Filed Dec. 21, 1953 E. SNYDER BRUSH BLOCK 2 Sheets-Sheet 2 o o o o --32 AGENT BRUSH BLOCK- Ellery P. Snyder, New York County, N. Y., assignor to Aviation vEngineering Division, Avien-Knickerbocker, In c,,Woodsi de,.N. Y.

Application. December 21, 1953,Serial No. 399,413 10 Claims. (Cl. 200--166) This invention relates to electrical contact making devices and particularly to brushmounting devices.

Prior art electrical brush mounting devices for positioning a number of brushes, commonly referred to as brush'blocks, generally exhibit'serious disadvantages. These disadvantages include: difficulty in replacing individualbrushes, requiring individual brush adjustment, large size and inability to withstand vibration.

An important advantage of the device of this invention is that the designer may pro-determine the brush pressure of the assembled unit without necessitating the delicate operation of adjustment of the individual brushes during assembly.

It is an object of thisinvention to provide a device to support, electrically isolated from each other, a plurality of brushes.

It is a different object of this invention to provide a brush mechanism operable in an environment subjecting it to severe vibration.

It is a further object of this invention to provide a compact multi-contact brush apparatus.

An object of thisinvention, is the provision of a brush block with replaceable brushes.

A particularobject of this invention is to provide a low-cost brush block.

For a more complete understanding of the present invention reference should be had to the following de tailed description taken in connection with the accompanying drawings.

In the drawings:

Figure 1 discloses pictorially a typical brush block of this invention in conjunction with rotary slip rings.

Figure 2 shows an exploded view of the components of the brush block.

Figure 3 is an end view of the brush block of this invention.

Figures 4 and 5 are elevation and cross-sectional side views of a preferred base element.

Figures 6 and 7 are elevation and cross-sectional side views of an alternate base element.

With reference to Figure 1, shaft 10 supports a plurality of electrically conductive rings 12, usually referred to as slip rings, electrically isolated from each other. Fingers 14 serve as brushes to make contact to electrically conductive rings 12. Leads 16 connecting to an electrical circuit are soldered to exposed terminal end 18 of the brush.

Referring now to exploded view of Figure 2, the brush block assembly is shown formed of three simple elements. The first is the contact-making finger or brush which is formed with a right angle bend 20 and a 90 twisted end portion 22. For many applications a suitable brush material has been found to be a spring tempered flat wire .005" thick, .030" wide formed of a 10K white gold alloy as provided by Baker & Co. of Newark, New Jersey, under the name Baker Alloy 1323. An insulating plastic base 30 is provided with a series of spaced holes 32 which are large enough in diameter to receive contact finger 10. Tubular channel 34 is deployed transversely to holes 32 so as to intersect them.

Plastic shaft 44 is a segment of a cylindrical member having a diameter D corresponding to that of channel 34.

Dimension 0. is small enough to permit clearance between base 30 and the shaft 44, when the parts are assembled as shown in Figure 3.

After assembly, shaft 44 is turned 90 by means of a screwdriver inserted in slot 46, to the position shown in United States Patent 9 Brush pressure against slip ring 12 should be approximately ten times the mass so that vibration will not pick the brush off the ring.

It is to be appreciated that the apparatus of this invention may be assembled from a surprisingly few parts. Further, the parts are simple and inexpensive and may be readily and quickly assembled by unskilled personnel thus permitting the low-cost production of the device.

in Figures 4 and 5 there is set forth the best mode contemplated for carrying out the invention.

Brush block base 54 is provided with a raised portion having slots 56 a into which the brushes are inserted. Bafiles 58 provide further insulation between brushes.

One method of making the block base is to drill a hole 34 in block 54;-formed of an electrical insulator such as phenol-formaldehyde impregnated cloth and then mill the slots 56. Alternately, the brush blocks of this invention may be molded, as by injection or transfer molding techniques.

In Figure G an extension of the baflle construction is shown, A base block is'provided with a hole 60 adapted to receive the slip ring assembly shown in Figure 1. Baffles 62 do not extend completely across the block thus providing a supporting Web 64 to which conventional given diameter and brush block shaft 44 having a given di-,

ameter D, the brush-pressure of the assembled unit will be a function of the cavity opening dimension 0 and radius r of the base 30.-

A typical device having a base member 1 x /8" x A1" can accommodate 20 brushes spaced apart.

It is to be appreciated that many modifications and additions may be made to adapt the apparatus to a specific installation without departing from the spirit of the invention.

What I claim as new is:

l. A brush contact assembly comprising: a plurality of contact-making elements; a base member formed of an electrical insulating material having a shaft opening extending therethrough; a shaft provided with annular grooves and adapted to fit said opening having a first radial dimension smaller than said shaft opening and a second radial dimension substantially the same as said shaft opening, said shaft being rotatable in said shaft opening so as to fixedly position said contact-making members in said grooves.

2. A brush contact assembly comprising: a base member formed of an electrical insulating material having a shaft opening extending therethrough and a plurality of holes intercepting said shaft opening; a plurality of contact-making elements having a first portion extending through said holes and a second portion at substantially right angles to said first portion extending upwardly above said base member; a shaft provided with annular grooves and adapted to fit said opening having a first radial dimension smaller than said shaft opening and a second radial dimension substantially the same as said shaft opening, said shaft being rotatable in said shaft opening so as to fixedly position said contact-making members in said grooves.

3. A contact-making apparatus comprising a brush holder having at least one exposed surface and provided with a channel having a wall extending inwardly from said exposed surface conforming to a cylinder generated about an axis parallel to and positioned less than the radius of said cylinder below said exposed surface, a plurality of brushes positioned substantially radially to said axis, a shaft member adapted to be inserted in said channel in a first position so as to provide clearance between said Patented Jan. 18, 1955..

3 shaft, said inwardly extending wall and 'said brushes and to lockingly fix said brushes when turned to a second position. 4. A brush contact assembly comprising: a plurality of contact-making elements; a base member formed of an electrical insulating material having an electrically insulating shaft provided with annular grooves and positioned in a shaft opening extending therethrough; said shaft having a first radial dimension smaller than said shaft opening and a second radial dimension substantially the same as said shaft opening, said shaft being rotatable in said shaft opening so as to fixedly position said contact-making members in said grooves.

5. A brush contact assembly comprising: a base mem ber formed of an electrical insulating material having a shaft opening extending therethrough and a plurality of holes intercepting said shaft opening; a plurality of contact-making elements having a terminal portion extending through said holes and a contact-making portion at substantially right angles to said terminal portion extending upwardly above said base member; a shaft adapted to fit said opening having a first radial dimension smaller than said shaft opening and a second radial dimension substantially the same as said shaft opening, said shaft being rotatable in said shaft opening so as to fixedly position said contact-making members in said grooves.

6. A contact-making apparatus comprising a brush holder having at least one exposed surface and provided with a channel having a wall extending inwardly from said exposed surface conforming to a cylinder generated about an axis parallel to and positioned less than the radius of said cylinder below said exposed surface, a plurality of brushes partially in said channel having an exposed terminal and contact-making portion, a shaft member adapted to be inserted in said channel in a first position so as to provide clearance between said shaft, said inwardly extending wall, and said brushes and to lockingly fix said brushes when turned to a second position.

7. A brush block having a base portion provided with an axially exposed cylindrical cavity having a plurality of holes extending outwardly from said cavity, brush members inserted in said holes, a shaft having annular grooves adapted to be inserted in said cavity and rotated to lock said brush members fixedly in position in said grooves.

8. A brush contact assembly comprising: a plurality of contact-making elements; a base member formed of an electrical insulating material having afirst shaft opening extending therethrough; a shaft provided with annular grooves and adapted to fit said first opening having a first radial dimension smaller than said shaft opening and a second radial dimension substantially the same as said shaft opening, said shaft being rotatable in said first shaft opening so as to fixedly position said contact-making members in said grooves and means for positioning a slip ring assembly in contact with said contact making members comprising a second shaft opening spaced from said first opening and parallel thereto having a plurality of slots aligned with said grooves intersecting said second shaft opening and means for supporting said shaft.

9. A brush contact assembly comprising: a base member formed of an electrical insulating material having a shaft opening extending therethrough and a plurality of holes intercepting said shaft opening; a plurality of flat contact-making elements bent to form a terminal portion extending through said holes and a portion extending upwardly above said base member having a portion twisted at right angles to the transverse axis of said element; a shaft adapted to fit said opening having a first radial dimension smaller than said shaft opening and a second radial dimension substantially the same as said shaft opening, said shaft being rotatable in said shaft opening so as to fixedly position said contact-making members in said grooves.

10. A brush block having a base portion provided with an axially exposed cylindrical cavity having a plurality of holes extending outwardly from said cavity, thin metal brush members inserted in said holes and bent so as to extend upwardly of said base portion, said upwardly bent portion having a portion twisted annular grooves adapted to be inserted in said cavity and rotated to lock said brush members fixedly in position in said grooves.

Fox Aug. 4, 1931 Obergfell Nov. 8, 1938 

